At long last, Microsoft to release Outlook .PST file specifications

Three weeks ago, the European Commission signaled its approval of Microsoft's revised plan for a more vendor-neutral Web browser selection screen for European Windows users. But that revised plan was buffered with a big bonus: a promise to supply the general public with a wealth of interoperability information, including about proprietary formats.

Among the most sought after formats on that list has been for Outlook Personal Folders -- the much-maligned .PST file format, whose lack of comprehension has been the pet peeve of certainly every developer who's ever worked on a calendar or smartphone synchronization utility. Now the manager for Microsoft's new Office Interoperability Group announced this morning that work is under way on public documentation for the file format.

"This will allow developers to read, create, and interoperate with the data in .PST files in server and client scenarios using the programming language and platform of their choice," reads Paul Lorimer's notice this morning. "The technical documentation will detail how the data is stored, along with guidance for accessing that data from other software applications. It also will highlight the structure of the .PST file, provide details like how to navigate the folder hierarchy, and explain how to access the individual data objects and properties."

Although Microsoft had already documented the Outlook Object Model, that was essentially the type library, or interface, for .NET applications to address components of the running Outlook 2007 application. That's only helpful if you're a developer of an add-on or some other product that assumes that Outlook is running. What Microsoft is promising today goes much deeper: As a Microsoft spokesperson told Betanews this afternoon, the specification will actually enable some organizations to finally comply with new government policies for corporate governance, especially with regard to maintenance of interoffice communications.

Back in March 2007, the issue of whether Outlook's ability to automatically delete old communications was brought to light by way of AMD's ongoing antitrust suit against Intel. At that time, Intel's attorneys claimed the company inadvertently destroyed much of the internal e-mails it had been ordered to keep, on account of an internal network policy enabling Outlook to destroy old .PST files. Knowing that such a loss was possible, Intel managers had instructed their staff to create new, personal .PST files that could not be destroyed.

Had a better understanding of the .PST file format been available at the time, theoretically, forensic engineers may have been able to recover deleted .PST material from backups, or from hard drives that were also in use for other purposes.

The documentation will be released under the company's Open Specification Promise, which was unveiled in February 2008 with the expectation that the .PST format would certainly be among those that the European Commission would expect to see opened up. But even after today's announcement, the matter of when the documentation would be released, was left undetermined. As Lorimer puts it, the amount of time Microsoft expects to take will be determined by how long "industry experts and interested customers" may take reviewing the drafts, "to ensure that it is clear and useful."